How to Create Custom Metrics in Facebook Ads | Step-by-Step Guide

If you're still relying on default Meta Ads metrics like CPM, CTR and ROAS, you're missing the big picture.

Because those numbers tell you activity—not outcomes. And outcomes are what drive profit.

If you're a small business trying to make smart, performance-based decisions on a limited budget, the default dashboard just won't cut it.

That’s why you need custom metrics.

In this issue of Digital Ad Snack, I’ll show you how to create them inside Facebook Ads Manager—so you can track what actually matters.

Let’s get into it. 👇

Why Default Meta Ad Metrics Aren’t Enough

Meta gives you dozens of metrics—CTR, CPM, CPC, ROAS, Reach…

But most of them are surface-level. And none of them are built around your actual business model.

That’s the problem:

What Meta cares about (delivery optimization) isn’t always what you care about (profit and growth).

A good example? Meta’s new Optimization Score.

It now shows up in every ad account—and it looks important.

But the truth is: it reflects Meta’s system health, not your business performance.

👉 It doesn't tell you if you’re profitable.

👉 It doesn’t know your margins.

👉 And it doesn’t know your goals.

So don’t let Meta auto-adopt those recommendations blindly.

The score might improve delivery mechanics—but it won’t guarantee results.

(We’ll dive deeper into this in a future issue.)

That’s where custom metrics come in.

They let you build performance tracking around your goals, your math, and your business logic—not Meta’s defaults.

How Custom Metrics Work in Meta Ads Manager

Custom metrics are formulas you build using existing metrics inside Meta Ads Manager.

You can use them to track profitability, creative performance, or any KPI that's missing from your dashboard.

Here’s where you find them:

Go to Ads Manager > Columns > Customize Columns > Create Custom Metric

From there, you can:

• Choose your input metrics

• Set the calculation (add, subtract, divide, etc.)

• Name and describe your metric

• Choose format: currency, number, or percentage

• Decide if the metric is private or shared with your team

🧩 Once created, they show up in your reporting views—and can be used in rules, dashboards, and performance reviews.

Step 1: Go to the Custom Metrics Builder

Step 2: Select Custom and hit “+Create custom metrics” to create a new one

Step 3: Input your Formula for your custom metric

Step-by-Step: How to Create Your First Custom Metric

Let’s walk through building a very important custom metric GPM (Gross Profit Margin) as an example.

1. Go to Ads Manager

Click Columns > Customize Columns > Create Custom Metric

2. Define Your Metric

Name: Gross Profit Margin (GPM)

Description: AOV (Average Order Value)- CPA (Cost Per Acquisition)

(For example you can add here the formula for everyone in the Ads Manager to understand it.)

Formula: Purchase Conversion Value – Cost Per Purchase

Format: Currency

This shows you how much profit you're making per order after ad costs—but before COGS. You can create a separate Net GPM metric if you have COGS data.

Hit save—and now it appears in your columns.

Do Custom Metrics Need to Be Created Separately in Each Ad Account?

Yes. Custom metrics are account-specific, which means you’ll need to recreate them in each Meta Ads account you manage.

They don’t carry over between Business Managers or Ad Accounts, so if you're running multiple stores or client accounts, you’ll need to build them manually in each one.

💡Pro tip:

When creating the metric, you can choose to share it across the account—so others with access (like team members or clients) can view and use it too.

Which Custom Metrics You Should Track in Facebook Ads

There’s no one-size-fits-all dashboard in Meta Ads.

The custom metrics you use should be dictated by what kind of business you run and what outcomes you care about most.

Too many SMBs track whatever Facebook shows by default—then wonder why their results don’t translate into profit.

Here’s a better way to approach it:

• If you're running product-driven offers (like eCommerce or DTC):

  Focus on Net POAS and GPM (Gross Profit Margin) to understand what’s actually profitable after costs.

• If you're optimizing for efficiency per sale (like lead gen, services, or high-ticket offers):

  Use PAAC (Profit After Ad Cost) to track total margin after ad spend.

• If you're testing and scaling creative:

  Track Hook Rate, Hold Rate, and Click-to-Landing Page View Rate to evaluate ad performance beyond CTR.

👉 The key is this: your ad metrics should match your business goals.

📉 Chasing CTR or ROAS without knowing margins is how you lose money.

📈 Tracking metrics like PAAC or GPM helps you scale profitably—because you're measuring what actually moves the needle.

Don’t just look at what’s easy to measure.

Track what actually matters to your bottom line.

🍩 Snackable Challenge

This week, go build at least one custom metric that reflects your real business goals.

✅ Go to Ads Manager and open the Custom Metric builder

✅ Create PAAC, GPM, and POAS

✅ Add it to your default column view and start using it in your decisions

Then hit reply and show me your new metric—I’d love to see how you’re moving beyond the basic.